On the Age and Genesis of the Verkhnyaya Gora Strata of the Kurtak Region, Middle Yenisei

Abstract

Abstract A study of the geology of the Verkhnyaya Gora strata in the Berezhekovo-5 section of the Kurtak geoarcheological region, based on numerous detailed outcrops, shows its deluvial-solifluctional genesis. The results of the analysis of the therio- and malacofaunas from the Verkhnyaya Gora strata suggest that the most probable age of host deposits, based on the summary of all available paleontological data, is early Neopleistocene. Most of the small mammal fauna from the Verkhnyaya Gora strata at the Berezhekovo-5 locality formed during the MQR 5 biochron (up to the boundary with the MQR 4 biochron) and corresponds to the level of late Vyatkino faunas of Western Siberia and late Tiraspol’ faunas of Eastern Europe. Ecological characteristics of the identified small mammal taxa allows the recognition of three biochronologically close but ecologically distinct faunal assemblages: steppe, forest-steppe, and periglacial. Considering the biochronological interpretation of the microtheriofauna, the presence of remains from multiple faunal assemblages in mixed state within the Verkhnyaya Gora strata can be explained by accumulation of paleontological material during the MQR 5 biochron against the background of changing landscape-climatic environments spanning Marine Isotope Stages (MIS) 16 to the onset of MIS 13. Thus, an early Quaternary age for the subaerial Verkhnyaya Gora strata in the stratotype Berezhekovo-5 section, Kurtak region, Yenisei River, is deemed substantiated for both the local stratigraphic scheme of the Minusinsk Basin and the regional stratigraphic scheme of the Altai-Sayan mountain region.